In lithography techniques, for example, a resist film composed of a resist material is formed on a substrate, and the resist film is subjected to selective exposure of radial rays such as light or electron beam through a mask having a predetermined pattern, followed by development, thereby forming a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portions become soluble in a developing solution is called a positive-type, and a resist material in which the exposed portions become insoluble in a developing solution is called a negative-type.
In recent years, in the production of semiconductor elements and liquid crystal display elements, advances in lithography techniques have led to rapid progress in the field of pattern miniaturization.
Typically, these miniaturization techniques involve shortening the wavelength (increasing the energy) of the exposure light source. Conventionally, ultraviolet radiation typified by g-line and i-line radiation has been used, but nowadays KrF excimer lasers and ArF excimer lasers are starting to be introduced in mass production of semiconductor elements. Furthermore, research is also being conducted into lithography techniques that use an exposure light source having a wavelength shorter (energy higher) than these excimer lasers, such as electron beam, extreme ultraviolet radiation (EUV), and X ray.
As a technique for providing a finer pattern, there is proposed a double patterning process for forming a resist pattern by performing patterning more than once. According to the double patterning process, for example, a first resist pattern is formed on a support by performing patterning using a first resist composition, then patterning is further performed on the support, on which the first resist pattern is formed, using a second resist composition, and thereby a resist pattern having higher resolution than the resist pattern formed by single patterning can be formed.
In JP-A-2013-164509, there is disclosed a method of forming a resist pattern, in which a first resist pattern is formed on a support, a SiO2 film is formed on the surface whereon the first resist pattern has formed, etching is performed using the SiO2 film as a sacrificial film, and then the first resist pattern is removed, thereby forming a second pattern of the SiO2 film.